5…Bxc3+In this line of play it is most important for Black to double White's Pawns on the Q B file and to stop the advance of these Pawns afterwards. White would therefore have done better to play B - Q 2 on his 5th move.
7.Ne2Having the intention of playing P - B 3 and P - K 4, White does not obstruct his K B P by Kt - B 3. But 7) B - R 3 would be better, to free the way for the Pawn at Q B 4.
10…e5Black plays very well. The blocked Pawn at Q B 3 deprives White of mobility. 11) P x K B P would be met by P - K 5, gaining a piece. Black now threatens to envelop the King's wing by P - B 5.
11.f4Obviating the danger just mentioned. If now 11) .... P x K B P, then 12) P x K B P.
19.Qh6The Queen can no longer guard the square Q 3. After 19) Kt x B, P x Kt; 20) Q - Kt 5 ch, Q - Kt 3 White could not play P - Q 5 on account of Kt - Kt 3. White, therefore, makes a combination, in order to secure for the lost Pawn an equivalent in the open K file and greater mobility of the Bishops.
25…Qxf2+Better was 25) .... P - Kt 3; 26) Q - Q 4, Kt - Kt 5; 27) B - K 3, Kt x B; 28) Q x Kt, B x P; 29) Kt - Kt 4, Q - B 5, and the passed Q R P should win.
31.Ke5By 31) P - R 4 he would have been able to draw, as with the Pawns at K Kt 3 and K R 4 Black has no points of attack on the King's side, whilst P - B 4 or K - B 5 - Kt 4 would suffice to make the Queen's side safe.
35…Bh3A stroke of genius. Black fixes the Pawn at R 2, and uses this almost imperceptible weakness to work out a winning combination.
42.Kg7As the White King has now gone away, in order to seek an equivalent for the K R P, the Black King starts for the Queen's side; for instance: 43) K x P, B x P; 44) P - R 4, P x P; 45) P x P, B - K 7; 46) K - R 6, P - Kt 4; 47) P - R 5, K - K 3; 48) B - B 8, K - Q 4; 49) K - Kt 5, B x P; 50) K x B, K - B 5; 51) K - Kt 4, P - Kt 5; 52) K - B 3, P - Kt 6; 53) B - R 3, K - B 6 and P - Kt 7, etc.
Emanuel Lasker, The International Chess Congress, St. Petersburg, 1909 (1910) · Public domain · source